package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/**
 * @author ZZQ
 * @version 1.0
 * 全局ID生成器
 */

@Component
public class RedisIdWorker {
    //开始的时间戳
    private static final long BEGIN_TIMESTAMP = 1640995200L;
    //位移次数
    private static final int COUNT_BITS = 32;

    @Resource
    private StringRedisTemplate stringRedisTemplate;


    public long nextId(String keyPrefix) {
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timeStamp = nowSecond - BEGIN_TIMESTAMP;

        //2.生成序列号
        //2.1获取当前日期，精确到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        //2.2自增长
        Long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);

        //拼接并返回
        return timeStamp << COUNT_BITS | count;
    }
}
